1. Technical Field:
The invention is related to the field of flush panel closure devices and in particular to submerged or flush closure latches or locking devices on flat panel doors for repeated openings and closings with front access only, wherein the closure device does not extend beyond the plane of the panel.
2. Background of the Invention:
The present invention fulfills the need for rapidly and repeatedly opening or unlocking and closing or locking panel doors to cabinets (or, more generally, locking removable portions to base structures) with the constraint that rear access to the cabinet is prohibited. At the same time, the invention fulfills the need for locking devices on panel doors which are flush or submerged with respect to the front plane of the panel door, so as to provide a strong lock which is rapidly unlockable from the front panel surface without any protruding devices at the front panel surface.
Typical locking devices on panels which are adapted for rapid and repeated convenient locking and unlocking of panels or panel doors typically include a rotatable handle which protrudes significantly from the front surface of the panel. This presents a significant problem, particularly in those cases where the panel is the outer or aerodynamic surface of a flight vehicle or aircraft. Such protrusions, even if slight, create non-laminar airflow patterns across the surface, greatly reducing the flight performance characteristics of the flight vehicle.
If the size of the handle is limited or minimized to reduce disturbance in the airflow pattern, then the leverage is reduced and either the locking force must be reduced or the user must exert an inconvenient amount of force to open the panel. If the locking force is reduced, the panel is less securely locked in place. On the other hand, if the user is forced to exert a relatively large force to open or unlock the panel, the rapidity with which the panel may be open and closed is greatly diminished, a significant disadvantage on busy flight lines.
Accordingly, some way of providing a panel lock which is flush (non-protruding) with respect to the panel outer surface, which hold the panel locked closed with a very large force but which is readily opened by a user outside the panel with a minimum application of force is needed.
Various techniques of locking movable members (such as window sashes and doors) with respect to another member (such as a window frame or opposing sash or cabinet) are known in the art. U.S. Pat. Nos. 559,663; 1,073,261 and 324,252 disclose window sash fasteners while U.S. Pat. No. 3,884,056 discloses a sliding door lock. In each of these references, there is a rotatable actuating member controlled by the user and a rotatable locking member actuated by the actuating member, both members rotating along parallel axes. As will be seen below, such arrangements with parallel axes of rotation have nothing to do with the solution to the problem reached by the present invention. This is because such arrangements require rotations perpendicular to the outer surface of the sash or door to be locked or unlocked, which is incompatible with any attempt to minimize protrusions of the locking device beyond the outer panel surface.
U.S. Pat. No. 199,916 and British Patent Document No. 613,589 each disclose devices similar to those discussed above, except that the actuating and locking members rotate about orthogonal axes. However, these two references merely concern braking a window sash against an adjacent surface such as the opposite sash or window frame, and have nothing to do with mechanical locking or interlocking. U.S. Pat. No. 1,531,487 also discloses a locking device in which the actuating and locking members rotate about orthogonal axes. However, this latter reference is directed to a locking device which pinches a lip protruding outwardly from a panel (a casket top). Such outward protrusions are to be avoided at all costs in the present invention.